onvel is a combination of begging for time, or taking as much time as possible (grovel) when partaking in a leisurely day-to-day pursuit such as going to the shops, the resulting combination will produce an amble, but in this specific context it is called an 'onvel'. Obviously a portmanteau of the words, grovel and amble would not create the word onvel, this word naturally rolls off the tongue of people in Merseyside.

man1: do you want to go to the shops today?

woman1: yeah, i wouldnt mind but as long as you dont onvel, last time you did that we ended up with 60 pounds worth of clothes from charity shops.